The Long Term Evolution (LTE) standard is a standard for wireless communication of high-speed data for mobile devices and data terminals. LTE is based on the GSM/EDGE (Global System for Mobile Communications/Enhanced Data rates for GSM Evolution) and UMTS/HSPA (Universal Mobile Telecommunications System/High Speed Packet Access) network technologies. Relative to GSM/EDGE and UMTS/HSPA, LTE may increase the capacity and speed of the wireless network based on improvements to the radio interface and improvements to the core network.
The LTE standard is based on packet switched IP networking and does not have inherent support for circuit-switched voice calls. Some telecommunications providers, when implementing the LTE standard, use the LTE network for data transmission while continuing to use other network standards/technologies, such as GSM or UMTS to handle voice calls. A number of approaches, however, have been developed to provide voice over LTE. One such approach is the Voice over LTE (VoLTE) standard.